Magnetic stirrer



2 SheerLs-Sheet l A. ROSINGER MAGNETIC STIRRER Filed Oct. 5, 1942 Q vfiw q /0 2 8 mm IIu/I 5 2 a H a w O U mmiflmm nu 1 O W x June 6, 1944.

FIG. I.

FIG. 2

June 1944- A. ROSINGER MAGNETIC STIRRER Filed Oct. 5, 1942 2Sheets-Sheet 2 J fig vi FIG.

INVENTOR. v ARTHUR ROSINGER Patented June 6, 1944 I UNITED STATES PATENTOFFICE I maon zzz gl iaana Applicat i ofiz cz lrr 460,841 6 Claims.('01. ass-10s) This invention relates to a stirring and mixing device,and has for its main object to provide a device of this character, whichwill operate by.

magnetic action, in a novel and efflcient manner.

Another object of my invention is to provide a device of the typementioned, in which a stirrer proper will be represented by an elementfree of movement and preferably unconnected, but which will react tomagnetic forces.

$till further objects of this invention will be apparent as thespecification of the same proceeds, and, among others, I may mention: Toprovide a device, as--indicatcd hereinbefore. which will automaticallyalign itself under the action of the magnetic-forces to an efflclentposition of operation, which will be operated by a permanent magnet,which will use highly magnetic alloys for such permanent magnet, whichwill be adapted to be used'for various operations, besides stirring ormixing, like grinding, pulverizing, etc., and in which the free magneticoperating element proper will be encased in an inert shell, so that themagnetic element will have no action on the material operated on.

In the drawings, forming a part of this speci- Fig. 2 is a sectionalview through the magnetic stirrer element proper, the section beingtaken on the line 2-2 of Fig. 1;

Fig. 3 is a plan view of the device illustrated in Fig. 1, portions ofthe same having been removed, and others being shown in section.

Referring now to the drawings more in detail, by characters ofreference, the numeral l0 indicates a casing or box, in general, havinga bottom Ii, side walls i2, and a removable top i3.

Secured in about the center of the box is an electric motor I, having avertical shaft i5, rotated by the same. The motor may be secured in anoperative position in said box or casing ill, by any appropriate means,as by having secured on the motor housing the bands i6 and ii, which maybe continued in arms it and I9, reaching to the respective side wallsi2, and being secured thereon, as at 20.

The electric motor may have the'usual wire connections 2i, leading to aregulating rheostat 22, and therethrough to a switch 23, and finally, inthis embodiment of the invention, to a usual plug 24, whereby it may beconnected into an electric feeding circuit.

A U shape or horseshoe permanent magnet,

generally indicated by the numeral 25, is secured on the shaftiS, asindicated at 26, so as to rotate therewith.

Overthe magnet 25, on the top or cover [3 of the casing I0, ,I place acontainer or vessel 21,

net 25 will have opposite magnetic polarity at their upper exposedterminations, as indicated by N and S, respectively, one terminationbeing north andthe other south polarity.

The magnetic stirrer element 29 in this embodiment is in the form of asmall circular rod, which will settle on the bottom 34 of the vessel 21in the position indicated in the Fig. 1, as will be obvious.

It also will be obvious that the respective ends of the magnetic stirrerrod 30 will take up polarities which will be opposite to the strong Nand S polarities of the magnet 25,a s also indicated in Fig. 1.

Now, when motor H, and the shaft is connected therewith, will be setinto rotation, magnet 25 will rotate therewith and will cause thestirrer element 29 to follow the same, said stirrer element describing arotary motion around its vertical center axis on the bottom 34 of thevessel 21 and thereby causing the liquid 28 to be strongly stirred andmixed.

The speed of rotation of the stirrer element proper 29 will depend onthe speed of rotation of the magnet 25, and may be increased ordecreased as necessary, by regulating the speed of the motor.

My experience has been that even without using extra strong magnets andvery high motor speeds, the liquid 28 may be stirred or mixed by mymethod in an eflicient manner and in a very short time, indeed, theupper surface of the liquid will take up a very deep curved contour,forming a deep vortex, thereby, of course, insuring a thorough mixingand stirring.

To aid in the eflicient operation of the device, I use a comparativelyheavy and strong permanent magnet 25, when desired made of any of thespecific, strongly magnetic alloys, well known in this art, and,similarly, a comparatively strong permanent magnet 30 for the stirringelement 29. I also make the neutral shell or cover 3| as thin aspossible and also make the top i3 of the casing i0 very thin and arrangethe operating top surfaces or terminations 35 and 36 of the magnet 25,as close to said top I: as possible, all these factors contributing to astrong action between the rotating magnet 25 and the stirrer 29.

The poles of the magnet 25 may be placed at .the two sides of thecontainer 21 and rotate GU therearound instead of underneath it.

It is also possible to use a magnet with a single operating pole beingmoved in -a predeter mined path outside of but close to the wall of thecontainer, thereby causing the magnetically responsive element withinthe container to follow 5 said predetermined path and perform thestirring and other operation on the medium in the container.

Obviously in a specific case, the magnet may be placed within the vesseland moved therein, and

similarly in a specific embodiment of my invention, the operatingelement may be secured to the wall of the vessel by a flexible cord,chain and the like,.still permitting considerable free movement along adesired path.

I also want to remark that the stirring element proper 30, and the like,obviously may be used without the inert or neutral shell or coveringindicated at 3i. I use such inert covering or shell,

the experiment without doing or watching the stirring operation with theadded advantage, that no rotating shaft is in the way of the'mixingoperation.

My novel magnetic operating element may be shaped according to the dutyto be performed by it, and, as has been indicated, it may be used notonly for stirring or mixing, but also for grinding and other appropriateoperations, and it may be made in larger or more powerful units foractual industrial work, and not only for laboratory purposes.

only where a magnetically responsive material of the operating elementproper, like .iron, steel, etc., would have a harmful effect on theliquid 28, indicated in the drawings, or on any other material withinthe container, and in such a case said shell or covering willbe of aninert or neutral character to the material or medium in the container,so as to have no effect thereon. Such covering will be selectedaccording to the purpose in view, and it may be made of porcelain,glass, Bakelite, an appropriate plastic, etc.

As has been indicated in the drawings, I prefer to use a permanentmagnet for the source of the magnetic effect, but of course, an electricmagnet also may be used, with appropriate construction for rotating orotherwise moving the same.

The movement of the magnet ma also be different from the describedcircular one, indeed, various types of relative movements may bedesigned between the vessel and the outer magnet,

moving either the vessel or the magnet, or both, for the purpose inview.

It also will be understood that the material of the vessel in which mymagnetic stirrer, grinder and the like, is to operate, must benonmagnetic, and, similarly, the casing ill, or other support for thecontainer, and similar auxiliary structure, also must be of nonmagneticmaterial.

In the drawings I indicated a rotary drive for the magnet 25, but, ofcourse, it may be moved in many other manners. as has been mentionedhereinbefore, and it may have other driving means than an electric.motor, it may even be moved manually, if desired.

The main novelty of my magnetic operating device is, that the operatingelement inside of a container or the like, is free to move and notconnected to any other part or element, as a rule,

and will have no mechanical construction to sup- 6 port or guide it.

In this manner, a stirring or other operation may be performed in anentirely closed vessel, no part projecting into the vessel, the contentsof the vessel may be easily placed under any pressure from highto'vacuum, no unnecessary vibrations, noise, electrical eiIects, etc.,are produced which may harmfully influence the opera- Another importantadvantage of my novel device, when used for grinding, pulverizing andsimilar operations, lies in the fact that the mag netic pull will beadded to the weight of the operating element and thereby the efliciencyof the operations will be increased.

My element may also easily be made self aligning, automatically keepingits axis of rotation.

I may mention that one specific form of using my device for quick andunusually eflicient stirring and mixing a liquid in a chemicallaborotory, which I tried, consists in placing the magnetic stirrerelement proper 29, eccentrically on the bottom of the container, thatis, to one side from the center, while the U-shaped magnet 25 remaincentrally placed, as shown in Fig. 1. In this case the magnetic stirrerproper 29, not only will rotate around its own center, but will, at thesame time, travel around on the bottom of the container, so that, to myobservation, stirrer element 29 will describe a composite movement whichI believe is epicyclic and the result in stirring eifect is, asmentioned, strikingly improved and quickened.

What I claim as new, is:

1. In a stirrer for chemical laboratories to be used for a liquidmedium, a container of nonmagnetic material for said medium, anelongated free moving stirrer element of magnetic material adapted to bedropped to the bottom of the container, a rotary U-shaped magnetvertically placed underneath said bottom with its poles closely thereto,and means to rotate said magnet on its vertical center'axis,. wherebyrotation of the U-shaped magnet will cause said magnet to describe apredetermined movement within said container.

2. In a stirrer, in the combination of claim 1, said magnetic stirrerelement being shorter than any transverse dimension of said bottom,

3. In a stirrer, in the combination of claim 1, said magnetic stirrerelement being shorter than the transverse dimensions of said bottom,said magnetic element being adapted to be placed eccentrically on oneside of the bottom, whereby it will be caused to describe an epicyclicmovement, travelling around and rotating on its axis, si-

0 multaneously.

4. In a stirrer, in the combination of claim 1,

a neutral coating on said magnetic stirrer element'to prevent aninteraction between said element and the liquid medium to be stirred bythe both, said magnetic element and said U-shaped,

magnet, being permanent magnets of high magnetic alloy.

ARTHUR RQSINGER.

combination of claim 1, I

